The present invention relates to power management and distribution systems, and more particularly to such systems having fault detection and isolation assemblies, as well as methods directed toward fault detection and isolation for such systems.
In typical electrical power generation and distribution systems, the measurement of currents on power wiring and protection of the wiring, as well as connected equipment, is needed in the event of failure. An aircraft is one illustrative example of an application for such systems. For aircraft systems, electrical energy is essential for continued flight when relying on electrical flight controls, and is also flight critical for electrically driven hydraulic pumps. Aircraft power systems may use a variety of power characteristics including AC (Alternating Current) or DC (Direct current) systems. Further typical variations of power types may include power sources, loads and distribution of nominal voltages including, but not limited to 28 Vdc, 270 Vdc, or 540 Vdc and 26 Vac, 115 Vac, and 230 Vac. The AC system types may also include Constant Frequency (CF), or Variable Frequency (VF) systems with a wide variation in output current and power ratings. Severe wiring or internal faults within these systems and within power distribution equipment panels or wiring may cause loss of power to these flight critical systems. Protective functions and assemblies within the power distribution systems improve flight safety by preventing or minimizing the effect of system or wiring faults. Rapid detection and isolation, as well as segregation, of short circuit faults are desirable due to the localized heating and damage that high current or arcs may cause.
Arcing type faults can be difficult to distinguish from normal non-linear or pulsed type load effects. Typical power systems have relied on current sensors at multiple locations on each wire segment and dedicated controllers and protection functions for each wire. These methods are large, heavy and expensive, have high power losses, or have other undesirable features.